Rocket Jumping
Fun with physics this, a technique of FPS players jumping and firing rockets at the ground in tandem, with the explosion then catapulting them into otherwise unreachable areas. Doom has a horizontal rocket 'leap', used to reach a secret exit in one level, and explosion-propelled jumps are also possible in golden oldie Rise of the Triad. But the original Quake was the first proper rocket jump fest.
It's possible that developer id knew about the rocket jump exploit in Quake, but unlikely that it could expectsuch balletic effortsto arise. Or that Quake's online multiplayer would eventually be ruled by the players that mastered the rocket jump, leaving inexperienced gamers with no way of competing with their high-leaping rivals. In Quake 3 even the AI competitors could rocket jump, though you'd need a wet brain rather than a techno-circuit to accomplish some of the game'smore complex rocket hops.
Team Fortress 2's soldier class is built purposefullyfor rocket jumps- he's tough, he carries a rocket-launcher, he jumps. Bingo. And as if it wasn't clear enough, Valve releaseda charmingly humourous trailerfor TF2 starring the rocket jumping soldier in all his graceful glory. Rocket jumping is alsoa vital speedrunner's tool, enabling whole sections of a game to be bypassed by riding a rocket, grenade or other explosive device. So, er, rocket on... (Sorry)
